Spacer



FIG. 1 is a perspective view of a spacer, showing my new design;

FIG. 2 is a front elevational view of the invention, of which the rear, left, and right side views are identical;

FIG. 3 is a top plan view of the invention; and,

FIG. 4 is a bottom plan view of the invention. 

The ornamental design for a spacer, as shown and described. 